Physical activity and television watching in relation to risk of type 2 diabetes: the Black Women's Health Study

Associations of Total and Domain-Specific Sedentary Time With Type 2 Diabetes in Taiwanese Older Adults

Background

The increasing prevalence of type 2 diabetes in older adults has become a public health concern. We investigated the associations of total and domain-specific sedentary time with risk of type 2 diabetes in older adults.

Methods

The sample comprised 1046 older people (aged ≥65 years). Analyses were performed using cross-sectional data collected via computer-assisted telephone-based interviews in 2014. Data on six self-reported domains of sedentary time (Measure of Older Adults’ Sedentary Time), type 2 diabetes status, and sociodemographic variables were included in the study. Binary logistic regression analysis was performed to calculate the adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for total and individual sedentary behavior components and likelihood of type 2 diabetes.

Results

A total of 17.5% of the participants reported type 2 diabetes. No significant associations were found between total sitting time and risk of type 2 diabetes, after controlling for confounding factors. After total sedentary behavior was stratified into six domains, only watching television for more than 2 hours per day was associated with higher odds of type 2 diabetes (OR 1.56; 95% CI, 1.10–2.21), but no significant associations were found between other domains of sedentary behavior (computer use, reading, socializing, transport, and hobbies) and risk of type 2 diabetes.

Conclusions

These findings suggest that, among domain-specific sedentary behavior, excessive television viewing might increase the risk of type 2 diabetes among older adults more than other forms of sedentary behavior.

Physical activity, sedentary behaviors and the incidence of type 2 diabetes mellitus: the Multi-Ethnic Study of Atherosclerosis (MESA)

BACKGROUND

The association between physical activity (PA), sedentary behavior, and incident diabetes has been assessed in whites but is less well investigated in multiethnic populations.

OBJECTIVE

To assess the association between PA, sedentary behavior, and incident diabetes in the Multi-Ethnic Study of Atherosclerosis.

RESEARCH DESIGN AND METHODS

Incident diabetes was assessed among adults without prevalent baseline diabetes (2000-2002) at 5 in-person examinations between 2002 and 2012. Baseline PA (moderate, vigorous, and exercise-specific; metabolic equivalents of task-hours/week) and sedentary behaviors (television watching, reading; hours/day) were assessed by questionnaire. HRs were estimated using Cox proportional hazard models.

RESULTS

Among 5829 adults (mean age 61.8 years, 54% female, 42% white, 12% Chinese-American, 26% African-American, 21% Hispanic-American), there were 655 incident diabetes cases (median follow-up 11.1 years). After adjustment, diabetes risk was lower in those with brisk or striding compared with none or casual walking pace (HR 0.67; 95% CI 0.54 to 0.84), higher levels of exercise PA (HR for highest vs lowest quartile 0.79; 95% CI 0.63 to 0.98), and any compared with no vigorous PA (HR 0.79; 95% CI 0.66 to 0.95). Race/ethnicity influenced the association of walking pace, exercise PA, and any vigorous PA on diabetes risk, which was only significant among whites. Total leisure sedentary behaviors (HR for highest vs lowest quartile 1.65; 95% CI 1.26 to 2.14) and television watching (HR for highest vs lowest quartile 2.68; 95% CI 1.38 to 5.21) were significantly associated with diabetes risk in multiethnic analyses and were influenced by race/ethnicity.

CONCLUSIONS

These results confirm the importance of PA and sedentary behavior on diabetes risk in a multiethnic population and demonstrate potential variations across race/ethnic groups.

Impact of Physical Activity on Glycemic Control and Insulin Resistance: A Study of Community-dwelling Diabetic Patients in Eastern China

Objective The aim of this study was to evaluate the relationship of various intensities of physical activity with glycemic control and insulin resistance in eastern China. Methods A population-based, cross-sectional study was conducted in eastern China. The subjects included 604 community-dwelling people. The participants were classified as insufficiently active (IA); sufficiently active (SA) and very active (VA) according to the International Physical Activity Questionnaire (IPAQ). Insulin sensitivity was assessed using the homeostasis model assessment of insulin resistance (HOMA-IR). Related social, biological, lifestyle factors and clinical characteristics were recorded and used as potential confounders. Results The cohort of 604 type 2 diabetes patients were classified according to the activity level: 107 subjects who were classified as IA, 329 met the criteria for SA, and the rest were VA. The proportion of obese patients, smokers, patients with hypertension, and the body weight, body mass index (BMI), waist circumference, hemoglobin A1c protein (HbA1c), and 2-h postprandial blood glucose (2hPG) were significantly lower in the SA and VA groups than in the IA group (p<0.05 or 0.01). The SA group had lower levels of fasting blood glucose (FPG) and HOMA-IR than the IA and VA groups (p<0.05 or 0.01). HOMA-IR was positively correlated with FPG, 2hPG, HbA1c, waist circumference and BMI. HOMA-IR was negatively correlated with the total walking activity (p<0.05). After adjusting for FPG, 2hPG, HbA1c, waist circumference and BMI among the groups, a partial correlation analysis showed a correlation between HOMA-IR and the total walking activity. Conclusion Physical activity is a significant factor regarding glycemic control and insulin sensitivity, although SA and walking may be superior to VA for ameliorating insulin sensitivity.

Associations of sitting behaviours with all-cause mortality over a 16-year follow-up: the Whitehall II study

BACKGROUND

Sitting behaviours have been linked with increased risk of all-cause mortality independent of moderate to vigorous physical activity (MVPA). Previous studies have tended to examine single indicators of sitting or all sitting behaviours combined. This study aims to enhance the evidence base by examining the type-specific prospective associations of four different sitting behaviours as well as total sitting with the risk of all-cause mortality.

METHODS

Participants (3720 men and 1412 women) from the Whitehall II cohort study who were free from cardiovascular disease provided information on weekly sitting time (at work, during leisure time, while watching TV, during leisure time excluding TV, and at work and during leisure time combined) and covariates in 1997-99. Cox proportional hazards models were used to investigate prospective associations between sitting time (h/week) and mortality risk. Follow-up was from date of measurement until (the earliest of) death, date of censor or July 31 2014.

RESULTS

Over 81 373 person-years of follow-up (mean follow-up time 15.7 ± 2.2 years) a total of 450 deaths were recorded. No associations were observed between any of the five sitting indicators and mortality risk, either in unadjusted models or models adjusted for covariates including MVPA.

CONCLUSIONS

Sitting time was not associated with all-cause mortality risk. The results of this study suggest that policy makers and clinicians should be cautious about placing emphasis on sitting behaviour as a risk factor for mortality that is distinct from the effect of physical activity.

Relationship of sitting time and physical activity with non-alcoholic fatty liver disease

BACKGROUND & AIMS

The goal of this study was to examine the association of sitting time and physical activity level with non-alcoholic fatty liver disease (NAFLD) in Korean men and women and to explore whether any observed associations were mediated by adiposity.

METHODS

A cross-sectional study was performed on 139,056 Koreans, who underwent a health examination between March 2011 and December 2013. Physical activity level and sitting time were assessed using the validated Korean version of the international Physical Activity Questionnaire Short Form. The presence of fatty liver was determined using ultrasonographic findings. Poisson regression models with robust variance were used to evaluate the association of sitting time and physical activity level with NAFLD.

RESULTS

Of the 139,056 subjects, 39,257 had NAFLD. In a multivariable-adjusted model, both prolonged sitting time and decreased physical activity level were independently associated with increasing prevalence of NAFLD. The prevalence ratios (95% CIs) for NAFLD comparing 5-9 and ⩾10 h/day sitting time to <5h/day were 1.04 (1.02-1.07) and 1.09 (1.06-1.11), respectively (p for trend <0.001). These associations were still observed in subjects with BMI <23 kg/m(2). The prevalence ratios (95% CIs) for NAFLD comparing minimally active and health-enhancing physically active groups to the inactive group were 0.94 (0.92-0.95) and 0.80 (0.78-0.82), respectively (p for trend <0.001).

CONCLUSIONS

Prolonged sitting time and decreased physical activity level were positively associated with the prevalence of NAFLD in a large sample of middle-aged Koreans, supporting the importance of reducing time spent sitting in addition to promoting physical activity.

Type II diabetes disparities in diverse women: the potential roles of body composition, diet and physical activity

The rates of diabetes in the USA are rapidly increasing, and vary widely across different racial/ethnic groups. This paper explores the potential contribution of body composition, diet and physical activity in explaining diabetes disparities across women of different racial and ethnic backgrounds. For body composition, racial/ethnic groups differ widely by BMI, distribution of body mass and quantity and type of adipose tissue. Dietary patterns that vary across race/ethnicity include consumption of meat, added sugars, high-glycemic carbohydrates and fast food. Additionally, physical activity patterns of interest include aerobic versus muscle-strengthening exercises, and the purpose of physical activity (leisure, occupation, or transportation). Overall, these variables provide a partial picture of the source of these widening disparities, and could help guide future research in addressing and reducing diabetes disparities.

Leisure-time, occupational, and commuting physical activity and risk of type 2 diabetes in Japanese workers: a cohort study

Background

Physical activity has been suggested to reduce the risk of type 2 diabetes. However, evidence is limited regarding whether vigorous-intensity activity yields the same benefits in preventing type 2 diabetes compared with an equivalent dose of moderate-intensity activity as well as other type of physical activity. We examined the risk of type 2 diabetes associated with exercise intensity during leisure and occupational and commuting physical activity among Japanese individuals.

Methods

Participants included 26,628 workers (23,207 men and 3,421 women) aged 30 to 64 years without diabetes at baseline. There was 6 years of follow-up maximum. Leisure-time exercise, occupational physical activity, and duration of walking to and from work were self-reported. Diabetes was diagnosed by using HbA_1c, fasting or random blood glucose, and self-report. We used Cox regression analysis to estimate the hazard ratio (HR) and the 95 % confidence interval (CI) of incident diabetes.

Results

During a mean follow-up of 5.2 years, 1,770 participants developed type 2 diabetes. Compared with individuals who engaged in no exercise, the HRs (95 % CIs) for <7.5, 7.5 to <15.0, and ≥15.0 MET-hours per week of exercise were 0.94 (0.81, 1.08), 1.07 (0.88, 1.30), and 0.90 (0.67, 1.21), respectively, among individuals who engaged in moderate-intensity exercise alone; 0.68 (0.44, 1.06), 0.86 (0.54, 1.34), and 0.89 (0.56, 1.41), respectively, among individuals who engaged in vigorous-intensity exercise alone; and 0.70 (0.44, 1.11), 0.57 (0.37, 0.90), and 0.76 (0.52, 1.11), respectively, among individuals who engaged in the two intensities, with adjustments for potential confounders and the total volume of exercise. Occupational physical activity and walking to and from work were not associated with diabetes.

Conclusions

The results suggest that vigorous-intensity exercise can reduce the risk of type 2 diabetes among Japanese workers.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-015-2362-5) contains supplementary material, which is available to authorized users.

Objectively Measured Sedentary Time and Cardiometabolic Biomarkers in US Hispanic/Latino Adults: The Hispanic Community Health Study/Study of Latinos (HCHS/SOL)

BACKGROUND

Sedentary behavior is recognized as a distinct construct from lack of moderate-vigorous physical activity and is associated with deleterious health outcomes. Previous studies have primarily relied on self-reported data, whereas data on the relationship between objectively measured sedentary time and cardiometabolic biomarkers are sparse, especially among US Hispanics/Latinos.

METHODS AND RESULTS

We examined associations of objectively measured sedentary time (via Actical accelerometers for 7 days) and multiple cardiometabolic biomarkers among 12 083 participants, aged 18 to 74 years, from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL). Hispanics/Latinos of diverse backgrounds (Central American, Cuban, Dominican, Mexican, Puerto Rican, and South American) were recruited from 4 US cities between 2008 and 2011. Sedentary time (<100 counts/min) was standardized to 16 hours/d of wear time. The mean sedentary time was 11.9 hours/d (74% of accelerometer wear time). After adjustment for moderate-vigorous physical activity and confounding variables, prolonged sedentary time was associated with decreased high-density lipoprotein cholesterol (P=0.04), and increased triglycerides, 2-hour glucose, fasting insulin, and homeostatic model assessment of insulin resistance (all P<0.0001). These associations were generally consistent across age, sex, Hispanic/Latino backgrounds, and physical activity levels. Even among individuals meeting physical activity guidelines, sedentary time was detrimentally associated with several cardiometabolic biomarkers (diastolic blood pressure, high-density lipoprotein cholesterol, fasting and 2-hour glucose, fasting insulin and homeostatic model assessment of insulin resistance; all P<0.05).

CONCLUSIONS

Our large population-based, objectively derived data showed deleterious associations between sedentary time and cardiometabolic biomarkers, independent of physical activity, in US Hispanics/Latinos. Our findings emphasize the importance of reducing sedentary behavior for the prevention of cardiometabolic diseases, even in those who meet physical activity recommendations.

Television watching and colorectal cancer survival in men

PURPOSE

To assess the association between pre- and postdiagnostic time spent sitting watching TV as well as other sedentary behaviors (other sitting at home and at work/driving) and mortality from colorectal cancer or other causes, and overall mortality.

METHODS

We followed stage I-III colorectal cancer patients from the Health Professionals Follow-up Study (1986-2010). Cox models were used to calculate hazard ratios (HRs) and 95 % confidence intervals (CIs).

RESULTS

A total of 926 and 714 patients were included in the analysis of pre- and postdiagnostic TV watching, respectively, and 471 and 325 died during follow-up. Prolonged prediagnostic TV viewing was associated with increased risk of colorectal cancer-specific mortality independent of leisure-time physical activity. The HRs (95 % CIs) for 0-6, 7-13, 14-20, and ≥21 h/week were 1.00 (referent), 0.84 (0.56-1.25), 1.15 (0.75-1.78), and 2.13 (1.31-3.45) (p trend = 0.01). The association was observed primarily among overweight and obese individuals. Prediagnostic TV watching was also associated with overall mortality within 5 years of diagnosis, largely due to the association with colorectal cancer mortality. Other prediagnostic sitting at home or at work/driving was not associated with mortality. Postdiagnostic TV viewing was associated with a nonsignificantly increased risk of colorectal cancer-specific mortality (HR for ≥21 vs 0-6 h/week = 1.45; 95 % CI 0.73-2.87) adjusting for TV viewing before diagnosis.

CONCLUSION

Prolonged prediagnostic TV watching is associated with higher colorectal cancer-specific mortality independent of leisure-time physical activity among colorectal cancer patients.

Association Between Daily Time Spent in Sedentary Behavior and Duration of Hyperglycemia in Type 2 Diabetes

Exercise and sedentary behavior have different physiologic effects, which have yet to be fully explained. Time spent in sedentary behavior has been associated with glucose intolerance in adults at risk for type 2 diabetes, but these data have come largely from cross-sectional studies that have not explored this relationship in adults with diabetes. The specific aim of this study was to examine the relationship between time spent in sedentary behavior and glucose levels in adults diagnosed with type 2 diabetes over 3-5 days.

METHODS

Using continuous and concurrent data gathered from wrist accelerometry and a Continuous Glucose-Monitoring Sensor (CGMS), we conducted a longitudinal, descriptive study involving 86 patients with type 2 diabetes.

RESULTS

More time spent in sedentary behavior was predictive of significant increases in time spent in hyperglycemia (B = 0.12, p < .05).

CONCLUSIONS

These findings highlight the relationship between time spent sedentary and time spent in hyperglycemia, as identified through our use of objective, continuous data collection methods for both sedentary behavior and glucose levels across multiple days (Actiwatch, CGMS). For patients with type 2 diabetes, these findings emphasize the need for the development of individualized interventions aimed at decreasing the amount of time spent in hyperglycemia by reducing sedentary time.

Physical activity and the risk of type 2 diabetes: a systematic review and dose-response meta-analysis

We investigated the association between specific types of physical activity and the risk of type 2 diabetes in a systematic review and meta-analysis of published studies. PubMed, Embase and Ovid databases were searched for prospective studies and randomized trials up to 2nd of March 2015. Summary relative risks (RRs) were calculated using a random effects model. Eighty-one studies were included. The summary RRs for high versus low activity were 0.65 (95 % CI 0.59-0.71, I(2) = 18 %, n = 14) for total physical activity, 0.74 (95 % CI 0.70-0.79, I(2) = 84 %, n = 55) for leisure-time activity, 0.61 (95 % CI 0.51-0.74, I(2) = 73 %, n = 8) for vigorous activity, 0.68 (95 % CI 0.52-0.90, I(2) = 93 %, n = 5) for moderate activity, 0.66 (95 % CI 0.47-0.94, I(2) = 47 %, n = 4) for low intensity activity, and 0.85 (95 % CI 0.79-0.91, I(2) = 0 %, n = 7) for walking. Inverse associations were also observed for increasing activity over time, resistance exercise, occupational activity and for cardiorespiratory fitness. Nonlinear relations were observed for leisure-time activity, vigorous activity, walking and resistance exercise (p nonlinearity < 0.0001 for all), with steeper reductions in type 2 diabetes risk at low activity levels than high activity levels. This meta-analysis provides strong evidence for an inverse association between physical activity and risk of type 2 diabetes, which may partly be mediated by reduced adiposity. All subtypes of physical activity appear to be beneficial. Reductions in risk are observed up to 5-7 h of leisure-time, vigorous or low intensity physical activity per week, but further reductions cannot be excluded beyond this range.

Definition, measurement, and health risks associated with sedentary behavior

PURPOSE AND METHODS

Although evidence is accumulating that sedentary behavior (SB), independent of moderate-to-vigorous intensity physical activity (MVPA), is associated with cardiometabolic and aging outcomes in adults, several gaps present opportunities for future research. This article reports on the "Research Evidence on Sedentary Behavior" session of the Sedentary Behavior: Identifying Research Priorities workshop, sponsored by the National Heart, Lung, and Blood Institute and the National Institute on Aging, which aimed to identify priorities in SB research.

RESULTS AND CONCLUSIONS

A consensus definition of SB has not yet been established, although agreement exists that SB is not simply all behaviors other than MVPA. The two most common definitions are as follows: one based solely on intensity (<1.5 metabolic equivalents [METs]) and another which combines low intensity (≤1.5 METs) with a seated or reclining posture. Thus, for the definition of SB, evaluation of whether or not to include a postural component is a research priority. SB assessment methodologies include self-report and objective measurement, each offering distinct information. Therefore, evaluation, standardization, and comparison across self-report and objective assessment methods are needed. Specific priorities include the development and validation of novel devices capable of assessing posture and standardization of research practices for SB assessment by accelerometry. The prospective evidence that SB relates to health outcomes is limited in that SB is almost exclusively measured by self-report. The lack of longitudinal studies with objectively measured SB was recognized as a major research gap, making examination of the association between objectively measured SB and adverse health outcomes in longitudinal studies a research priority. Specifically, studies with repeated measures of SB, evaluating dose-response relationships, with inclusion of more diverse populations are needed.

A randomized controlled exercise training trial on insulin sensitivity in African American men: The ARTIIS study: Major category: study design, statistical design, study protocols

BACKGROUND

Lack of regular physical activity at prescribed intensity levels is a modifiable risk factor for insulin resistance and the development of diabetes. African American men are at increased risk for developing diabetes and most African American men are not meeting the current recommended levels of physical activity. The primary objective of the Aerobic Plus Resistance Training and Insulin Resistance in African American Men (ARTIIS) study is to determine the effectiveness of an exercise training intervention aimed at reducing diabetes risk factors in African American men at risk for developing diabetes.

METHODS

Insufficiently active 35-70 year old African American men with a family history of diabetes were eligible for the study. The 5-month randomized controlled trial assigns 116 men to an exercise training or healthy living control arm. The exercise training arm combines aerobic and resistance training according to the current national physical activity recommendations and is conducted in community (YMCA) facilities. The healthy living arm receives information promoting healthy lifestyle changes.

OUTCOMES

Insulin response to an oral glucose load is the primary outcome measure, and changes in physiological parameters, cardiorespiratory fitness, strength, body composition, and psychological well-being comprise the secondary outcomes.

CONCLUSIONS

The ARTIIS study is one of the first adequately powered, rigorously designed studies to investigate the effects of an aerobic plus resistance exercise training program and to assess adherence to exercise training in community facilities, in African American men.

Night-shift work and incident diabetes among African-American women

AIMS/HYPOTHESIS

The aim of this study was to assess shift work in relation to incident type 2 diabetes in African-American women.

METHODS

In the Black Women's Health Study (BWHS), an ongoing prospective cohort study, we followed 28,041 participants for incident diabetes during 2005-2013. They answered questions in 2005 about having worked a night shift. We estimated HR and 95% CIs for incident diabetes using Cox proportional hazards models. The basic multivariable model included age, time period, family history of diabetes, education and neighbourhood socioeconomic status. In further models, we controlled for lifestyle factors and BMI.

RESULTS

Over the 8 years of follow-up, there were 1,786 incident diabetes cases. Relative to never having worked the night shift, HRs (95% CI) for diabetes were 1.17 (1.04, 1.31) for 1-2 years of night-shift work, 1.23 (1.06, 1.41) for 3-9 years and 1.42 (1.19, 1.70) for ≥ 10 years (p-trend < 0.0001). The monotonic positive association between night-shift work and type 2 diabetes remained after multivariable adjustment (p-trend = 0.02). The association did not vary by obesity status, but was stronger in women aged <50 years.

CONCLUSIONS/INTERPRETATION

Long duration of shift work was associated with an increased risk of type 2 diabetes. The association was only partially explained by lifestyle factors and BMI. A better understanding of the mechanisms by which shift work may affect the risk of diabetes is needed in view of the high prevalence of shift work among workers in the USA.

Sedentary time and its association with risk for disease incidence, mortality, and hospitalization in adults: a systematic review and meta-analysis

BACKGROUND

The magnitude, consistency, and manner of association between sedentary time and outcomes independent of physical activity remain unclear.

PURPOSE

To quantify the association between sedentary time and hospitalizations, all-cause mortality, cardiovascular disease, diabetes, and cancer in adults independent of physical activity.

DATA SOURCES

English-language studies in MEDLINE, PubMed, EMBASE, CINAHL, Cochrane Library, Web of Knowledge, and Google Scholar databases were searched through August 2014 with hand-searching of in-text citations and no publication date limitations.

STUDY SELECTION

Studies assessing sedentary behavior in adults, adjusted for physical activity and correlated to at least 1 outcome.

DATA EXTRACTION

Two independent reviewers performed data abstraction and quality assessment, and a third reviewer resolved inconsistencies.

DATA SYNTHESIS

Forty-seven articles met our eligibility criteria. Meta-analyses were performed on outcomes for cardiovascular disease and diabetes (14 studies), cancer (14 studies), and all-cause mortality (13 studies). Prospective cohort designs were used in all but 3 studies; sedentary times were quantified using self-report in all but 1 study. Significant hazard ratio (HR) associations were found with all-cause mortality (HR, 1.240 [95% CI, 1.090 to 1.410]), cardiovascular disease mortality (HR, 1.179 [CI, 1.106 to 1.257]), cardiovascular disease incidence (HR, 1.143 [CI, 1.002 to 1.729]), cancer mortality (HR, 1.173 [CI, 1.108 to 1.242]), cancer incidence (HR, 1.130 [CI, 1.053 to 1.213]), and type 2 diabetes incidence (HR, 1.910 [CI, 1.642 to 2.222]). Hazard ratios associated with sedentary time and outcomes were generally more pronounced at lower levels of physical activity than at higher levels.

LIMITATION

There was marked heterogeneity in research designs and the assessment of sedentary time and physical activity.

CONCLUSION

Prolonged sedentary time was independently associated with deleterious health outcomes regardless of physical activity.

PRIMARY FUNDING SOURCE

None.

Television watching and risk of colorectal adenoma

Background:

Prolonged TV watching, a major sedentary behaviour, is associated with increased risk of obesity and diabetes and may involve in colorectal carcinogenesis.

Methods:

We conducted a cross-sectional analysis among 31 065 men with ⩾1 endoscopy in the Health Professionals Follow-up Study (1988–2008) to evaluate sitting while watching TV and its joint influence with leisure-time physical activity on risk of colorectal adenoma. Logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs).

Results:

Prolonged sitting while watching TV was significantly associated with increased risk of colorectal adenoma (n=4280), and adjusting for physical activity or a potential mediator body mass index did not change the estimates. The ORs (95% CIs) across categories of TV watching (0–6, 7–13, 14–20, and 21+ h per week) were 1.00 (referent), 1.09 (1.01–1.17), 1.16 (1.06–1.27), and 1.10 (0.97–1.25) (OR per 14-h per week increment=1.11; 95% CI: 1.04–1.18; P_trend=0.001). Compared with the least sedentary (0–6 h per week of TV) and most physically active (highest quintile) men, the most sedentary (14+ h per week) and least active (lowest quintile) men had a significant increased risk of adenoma (OR=1.25; 95% CI: 1.05–1.49), particularly for high-risk adenoma.

Conclusions:

Prolonged TV viewing is associated with modest increased risk of colorectal adenoma independent of leisure-time physical activity and minimally mediated by obesity.

Dietary patterns and physical inactivity, two contributing factors to the double burden of malnutrition among adults in Burkina Faso, West Africa

A population-based cross-sectional study was carried out in the northern neighbourhoods of Ouagadougou (Burkina Faso), to examine the relationship of nutritional deficiencies and cardiometabolic risk factors (CMRF) with lifestyle in adults. We randomly selected 330 households stratified by income tertile. In each income stratum, 110 individuals aged 25-60 years and having lived in Ouagadougou for at least 6 months were randomly selected. We performed anthropometric, dietary intake and physical activity measurements, and blood sample collection. Cluster analysis of dietary intake identified two dietary patterns: 'urban' (29 % of subjects) and 'traditional' (71 %). The 'urban' cluster exhibited a higher intake of fat and sugar, whereas a higher intake of plant protein, complex carbohydrate and fibre was observed in the 'traditional' pattern. Female sex, low income and lack of education were associated with the 'traditional' cluster, as well as Fe and vitamin A deficiency. CMRF prevalence (abdominal obesity, hypertension, hyperglycaemia, dyslipidaemia) was similar in both clusters. Subjects in the 'traditional' cluster spent more time in physical activity and had less sedentary time than those in the 'urban' cluster. 'Traditional' dietary pattern, low income, female sex and sedentary time were significant contributing factors to the double burden of malnutrition. The rapid nutrition transition is reflected in this co-occurrence of CMRF and nutritional deficiencies. This stresses the need for prevention strategies addressing both ends of the nutrition spectrum.

A prospective study of physical activity and breast cancer incidence in African-American women

BACKGROUND

Physical activity has been associated with reduced risk of breast cancer. Evidence on the association in African Americans is limited.

METHODS

With prospective data from the Black Women's Health Study, we assessed vigorous exercise and walking in relation to incidence of invasive breast cancer overall (n = 1,364), estrogen receptor-positive (ER(+), n = 688) cancer, and estrogen receptor-negative (ER(-), n = 405) cancer, based on 307,672 person-years of follow-up of 44,708 African-American women ages 30 years or older at enrollment. Cox proportional hazards models estimated incidence rate ratios (IRR) and 95% confidence intervals (CI).

RESULTS

Vigorous exercise at baseline was inversely associated with overall breast cancer incidence (Ptrend = 0.05): the IRR for ≥7 h/wk relative to <1 h/wk was 0.74 (95% CI, 0.57-0.96). The association did not differ by ER status. Brisk walking for ≥7 h/wk was associated with a reduction similar to that for vigorous exercise. Vigorous exercise at the age of 30 years, 21 years, or in high school was not associated with breast cancer incidence. Sitting for long periods at work or watching TV was not significantly associated with breast cancer incidence.

CONCLUSION

High levels of vigorous exercise or brisk walking may be associated with a reduction in incidence of breast cancer in African-American women.

IMPACT

These results provide informative data on a potential modifiable risk factor, exercise, for breast cancer in African-American women.

Social and physical environmental correlates of adults' weekend sitting time and moderating effects of retirement status and physical health

Emerging research suggests that prolonged sedentary behaviour (SB) is detrimental to health. Changes in SB patterns are likely to occur during particular life stages, for example at retirement age (55–65-year-old). Evidence on socio-ecological SB correlates is scarce and inconsistent in this age group. Moreover, the influence of socio-ecological correlates may vary depending on health and retirement status. This study examined social and environment correlates of overall weekend day sitting among adults at or approaching retirement age, and moderating effects of perceived physical health and retirement status. Baseline data from the Wellbeing, Eating and Exercise for a Long Life study in 2839 Australian adults (55–65-year-old) were analysed. Participants self-reported proximal social factors, neighbourhood social and physical environment, physical health and retirement status. MLwiN multilevel regression analyses were conducted. In the multivariable model, only social support from friends/colleagues to discourage sitting (B = −0.891; p = 0.036) was associated with overall weekend day sitting. No moderation of retirement status, nor physical health were found in the multivariable results. Results from this study suggest the importance of social factors in relation to weekend day sitting among 55–65-year-old adults. Health promotion initiatives in this age group should pay special attention to enhancing social interaction opportunities. Moreover, findings suggest that SB-specific correlates may need to be examined in future research.

Sedentary behavior as a mediator of type 2 diabetes

Over the past 5 years, the fastest growing new area of physical activity research centered around the concept that the large amount of time people spend sitting inactive may have significant physiological consequences hazardous to human health, including risk for type 2 diabetes and poor metabolism of lipids and glucose. Meta-analysis (10 studies) suggests there is a 112% greater relative risk associated with a large duration of sedentary behavior for type 2 diabetes. Meta-analysis also indicates significantly greater odds for metabolic syndrome. We also summarize results for 7 studies using objective measures of total sedentary time and focusing on cardiometabolic risks in persons at high risk for type 2 diabetes or already diagnosed with type 2 diabetes. The underlying hypothesis introduced in 2004 by the inactivity physiology paradigm has been that frequent and abundant contractile activity by certain types of skeletal muscle can have a potent influence on key physiological processes, even when the intensity is below that achieved through exercise. We explain some of the mechanisms for why the metabolism in slow-twitch oxidative skeletal muscle is key for understanding the healthy responses to low-intensity physical activity (LIPA). Findings from objective measures from inclinometry indicated that the quartile range for weekly sedentary time is ∼29 h/week. The total daily time that people sit, stand, and accumulate nonexercise steps is independent of traditionally recommended moderate-vigorous physical activity. The large amount of sedentary time associated with risk for disease can only be reduced significantly with safe and nonfatiguing LIPA, especially in the most at-risk proportion of the population. Importantly, experimental studies are starting to indicate that it will be especially insightful to understand the acute dose-response effects of LIPA in order to understand why reducing sedentary time can improve lipid and glucose metabolism for the prevention and treatment of chronic disorders related to type 2 diabetes.

Depressive symptoms, antidepressant use, and the incidence of diabetes in the Black Women's Health Study

OBJECTIVE

To assess the relationship of depressive symptoms and use of antidepressants with incident type 2 diabetes in prospective data from a large cohort of U.S. African American women.

RESEARCH DESIGN AND METHODS

The Black Women's Health Study (BWHS) is an ongoing prospective cohort study. We followed 35,898 women from 1999 through 2011 who were without a diagnosis of diabetes and who had completed the Center for Epidemiologic Studies Depression Scale (CES-D) in 1999. CES-D scores were categorized as <16, 16-22, 23-32, and ≥33, which reflected increasingly more depressive symptoms. We estimated incidence rate ratios (IRRs) and 95% CIs for incident diabetes using Cox proportional hazards models. The basic multivariable model included age, time period, family history of diabetes, and education. In further models, we controlled for lifestyle factors and BMI. We also assessed the association of antidepressant use with incident diabetes.

RESULTS

Over 12 years of follow-up, there were 3,372 incident diabetes cases. Relative to CES-D score <16, IRRs (95% CI) of diabetes for CES-D scores 16-22, 23-32, and ≥33 were 1.23 (1.12-1.35), 1.26 (1.12-1.41), and 1.45 (1.24-1.69), respectively, in the basic multivariate model. Multiple adjustment for lifestyle factors and BMI attenuated the IRRs to 1.11 (1.01-1.22), 1.08 (0.96-1.22), and 1.22 (1.04-1.43). The adjusted IRR for antidepressant use was 1.26 (1.11-1.43). Results were similar among obese women.

CONCLUSIONS

Both depressive symptoms and antidepressant use are associated with incident diabetes among African American women. These associations are mediated in part, but not entirely, through lifestyle factors and BMI.

Physical activity, sedentary time and gain in overall and central body fat: 7-year follow-up of the ProActive trial cohort

OBJECTIVE

The objective of this study is to examine the independent associations of time spent in moderate-to-vigorous physical activity (MVPA) and sedentary (SED-time), with total and abdominal body fat (BF), and the bidirectionality of these associations in adults at high risk of type 2 diabetes.

DESIGN AND SUBJECTS

We measured MVPA (min per day) and SED-time (h per day) by accelerometry, and indices of total (body weight, fat mass (FM), BF% and FM index) and abdominal BF (waist circumference (WC)) using standard procedures in 231 adults (41.3 ± 6.4 years) with parental history of type 2 diabetes (ProActive UK) at baseline, 1-year and 7-year follow-up. Mixed effects models were used to quantify the independent associations (expressed as standardised β-coefficients (95% confidence interval (CI))) of MVPA and SED-time with fat indices, using data from all three time points. All models were adjusted for age, sex, intervention arm, monitor wear time, follow-up time, smoking status, socioeconomic status and MVPA/SED-time.

RESULTS

MVPA was inversely and independently associated with all indices of total BF (for example, 1 s.d. higher MVPA was associated with a reduction in FM, β = -0.09 (95% CI: -0.14, -0.04) s.d.) and abdominal BF (for example, WC: β = -0.07 (-0.12, -0.02)). Similarly, higher fat indices were independently associated with a reduction in MVPA (for example, WC: β = -0.25 (-0.36, -0.15); FM: β = -0.27 (-0.36, -0.18)). SED-time was positively and independently associated with most fat indices (for example, WC: β = 0.03 (-0.04, 0.09); FM: β = 0.10 (0.03, 0.17)). Higher values of all fat indices independently predicted longer SED-time (for example, WC: β = 0.10 (0.02, 0.18), FM: β = 0.15 (0.07, 0.22)).

CONCLUSIONS

The associations of MVPA and SED-time with total and abdominal BF are bidirectional and independent among individuals at high risk for type 2 diabetes. The association between BF and MVPA is stronger than the reciprocal association, highlighting the importance of considering BF as a determinant of decreasing activity and a potential consequence. Promoting more MVPA and less SED-time may reduce total and abdominal BF.

Using accelerometers to measure physical activity in large-scale epidemiological studies: issues and challenges

BACKGROUND

The current guidelines for aerobic activity require that adults carry out ≥150 min/week of moderate-intensity physical activity, with a large body of epidemiological evidence showing this level of activity to decrease the incidence of many chronic diseases. Less is known about whether light-intensity activities also have such benefits, and whether sedentary behaviour is an independent predictor of increased risks of these chronic diseases, as imprecise assessments of these behaviours and cross-sectional study designs have limited knowledge to date.

METHODS

Recent technological advances in assessment methods have made the use of movement sensors, such as the accelerometer, feasible for use in longitudinal, large-scale epidemiological studies. Several such studies are collecting sensor-assessed, objective measures of physical activity with the aim of relating these to the development of clinical endpoints. This is a relatively new area of research; thus, in this article, we use the Women's Health Study (WHS) as a case study to illustrate the challenges related to data collection, data processing and analyses of the vast amount of data collected.

RESULTS

The WHS plans to collect 7 days of accelerometer-assessed physical activity and sedentary behaviour in ~18 000 women aged ≥62 years. Several logistical challenges exist in collecting data; nonetheless, as of 31 August 2013, 11 590 women have already provided some data. In addition, the WHS experience on data reduction and data analyses can help inform other similar large-scale epidemiological studies.

CONCLUSIONS

Important data on the health effects of light-intensity activity and sedentary behaviour will emerge from large-scale epidemiological studies collecting objective assessments of these behaviours.

Physical activity and the incidence of obesity in young African-American women

BACKGROUND

Obesity occurs more commonly among African-American women than among other racial/ethnic groups, and most weight gain occurs before middle age.

PURPOSE

The study prospectively investigated the relationship of vigorous exercise and brisk walking to the incidence of obesity (BMI ≥ 30) among African-American women aged <40 years.

METHODS

During 1995-2009 in the Black Women's Health Study, the current authors followed 20,259 African-American women who were aged <40 years and not obese at baseline. BMI, exercise, and walking were assessed at baseline and on biennial follow-up questionnaires. Data for BMI were collected through 2009. Data for exercise and walking were collected through 2007. Validation and reproducibility data indicated that reporting was more accurate for vigorous exercise than for brisk walking. Cox proportional hazards models estimated incidence rate ratios (IRRs) and 95% CIs of incident obesity for hours/week of vigorous exercise and walking relative to "little or no exercise" (<1 hour/week of vigorous exercise and <1 hour/week of brisk walking). The analyses were conducted in 2012.

RESULTS

The incidence of obesity decreased with increasing vigorous exercise; the IRR was 0.77 (95% CI=0.69, 0.85) for ≥ 7 hours/week relative to little or no exercise; the IRRs were reduced both among women with a healthy weight (BMI <25) at baseline and among women who were overweight (BMI 25-<30) at baseline. The IRRs for brisk walking for exercise and walking for transport were <1.0 for most levels of walking, but without clear trends of decreasing risk with increasing time spent walking.

CONCLUSIONS

The results suggest that vigorous exercise may reduce the incidence of obesity among young African-American women. Results for brisk walking were inconclusive.

Using the SenseCam to improve classifications of sedentary behavior in free-living settings

BACKGROUND

Studies have shown relationships between important health outcomes and sedentary behavior, independent of physical activity. There are known errors in tools employed to assess sedentary behavior. Studies of accelerometers have been limited to laboratory environments.

PURPOSE

To assess a broad range of sedentary behaviors in free-living adults using accelerometers and a Microsoft SenseCam that can provide an objective observation of sedentary behaviors through first person-view images.

METHODS

Participants were 40 university employees who wore a SenseCam and Actigraph accelerometer for 3-5 days. Images were coded for sitting and standing posture and 12 activity types. Data were merged and aggregated to a 60-second epoch. Accelerometer counts per minute (cpm) of <100 were compared with coded behaviors. Sensitivity and specificity analyses were performed. Data were collected in June and July 2011 and analyzed in April 2012.

RESULTS

TV viewing, other screen use, and administrative activities were correctly classified by the 100-cpm cutpoint. However, standing behaviors also fell under this threshold, and driving behaviors exceeded it. Multiple behaviors occurred simultaneously. A nearly 30-minute per day difference was found in sedentary behavior estimates based on the accelerometer versus the SenseCam.

CONCLUSIONS

Researchers should be aware of the strengths and weaknesses of the 100-cpm accelerometer cutpoint for identifying sedentary behavior. The SenseCam may be a useful tool in free-living conditions to better understand health behaviors such as sitting.

Sitting behavior and obesity: evidence from the Whitehall II study

BACKGROUND

Prospective studies report associations between indicators of time spent sitting and obesity risk. Most studies use a single indicator of sedentary behavior and are unable to clearly identify whether sedentary behavior is a cause or a consequence of obesity.

PURPOSE

To investigate cross-sectional and prospective associations between multiple sitting time indicators and obesity and examine the possibility of reverse causality.

METHODS

Using data from the Whitehall II cohort, multiple logistic models were fitted to examine associations between prevalent obesity (BMI ≥30) at Phase 5 (1997-1999), and incident obesity between Phases 5 and 7 (2003-2004) across four levels of five sitting exposures (work sitting, TV viewing, non-TV leisure-time sitting, leisure-time sitting, and total sitting). Using obesity data from three prior phases (1985-1988, 1991-1993; and recalled weight at age 25 years), linear regression models were fitted to examine the association between prior obesity and sitting time at Phase 5. Analyses were conducted in 2012.

RESULTS

None of the sitting exposures were associated with obesity either cross-sectionally or prospectively. Obesity at one previous measurement phase was associated with a 2.43-hour/week (95% CI=0.07, 4.78) increase in TV viewing; obesity at three previous phases was associated with a 7.42-hour/week (95% CI=2.7, 12.46) increase in TV-viewing hours/week at Phase 5.

CONCLUSIONS

Sitting time was not associated with obesity cross-sectionally or prospectively. Prior obesity was prospectively associated with time spent watching TV per week but not other types of sitting.

Novel views on new-onset diabetes after transplantation: development, prevention and treatment

New-onset diabetes after transplantation (NODAT) is associated with increased risk of allograft failure, cardiovascular disease and mortality, and therefore, jeopardizes the success of renal transplantation. Increased awareness of NODAT and the prediabetic states (impaired fasting glucose and impaired glucose tolerance, IGT) has fostered previous and present recommendations, based on the management of type 2 diabetes mellitus (T2DM). Unfortunately, the idea that NODAT merely resembles T2DM is potentially misleading, because the opportunity to initiate adequate anti-hyperglycaemic treatment early after transplantation might be given away for 'tailored' immunosuppression in patients who have developed NODAT or carry personal risk factors. Risk factor-independent mechanisms, however, seem to render postoperative hyperglycaemia with subsequent development of overt or 'full-blown' NODAT, the unavoidable consequence of the transplant and immunosuppressive process itself, at least in many cases. A proof of the concept that timely preventive intervention with exogenous insulin against post-transplant hyperglycaemia may decrease NODAT was recently provided by a small clinical trial, which is awaiting confirmation from a multicentre study. However, because early insulin therapy aimed at beta-cell protection seems to contrast the currently recommended, stepwise approach of 'watchful waiting' prior to pancreatic decompensation, we here aim at reviewing recent concepts regarding the development, prevention and treatment of NODAT, some of which seem to challenge the traditional view on T2DM and NODAT. In summary, we suggest a novel, risk factor-independent management approach to NODAT, which includes glycaemic monitoring and anti-hyperglycaemic treatment in virtually everybody after transplantation. This approach has widespread implications for future research and is intended to tackle NODAT and also ultimately cardiovascular disease.

Physical activity and pregnancy: past and present evidence and future recommendations

PURPOSE

In this review, we provide researchers and practitioners with an overview of the physical activity and pregnancy literature to promote prenatal physical activity, improve measurement, further elucidate the role of activity in reducing maternal health complications, and inform future research.

METHOD

We examined past and present physical activity and pregnancy studies and highlight key papers with a focus on maternal health outcomes to best inform physical activity promotion efforts.

RESULTS

We discuss: (a) historical overview of prenatal physical activity relative to the physical activity guidelines, how they have changed over time, and how evidence of the effect of prenatal activity on maternal/fetal health outcomes has affected clinical recommendations; (b) existing tools and challenges associated with measuring prenatal physical activity; (c) empirical evidence on multilevel determinants of prenatal activity to guide future intervention work; (d) empirical evidence of prenatal activity on adverse maternal outcomes (gestational diabetes mellitus, preeclampsia, excessive gestational weight gain) from observational and intervention studies; and (e) summary/recommendations for future research and practice.

CONCLUSIONS

The physical activity and pregnancy literature has evolved over the past 50 years, and there is sufficient empirical evidence to support the promotion of moderate-to-vigorous prenatal physical activity for maternal health benefits. Future studies and interventions should be carefully designed, theoretically driven, and include validated and reliable activity measures. Researchers and practitioners should also consider the multifaceted determinants and outcomes of prenatal physical activity and intervene to promote physical activity before, during, and after pregnancy.

Sedentary time in adults and the association with diabetes, cardiovascular disease and death: systematic review and meta-analysis

AIMS/HYPOTHESIS

Sedentary (sitting) behaviours are ubiquitous in modern society. We conducted a systematic review and meta-analysis to examine the association of sedentary time with diabetes, cardiovascular disease and cardiovascular and all-cause mortality.

METHODS

Medline, Embase and the Cochrane Library databases were searched for terms related to sedentary time and health outcomes. Cross-sectional and prospective studies were included. RR/HR and 95% CIs were extracted by two independent reviewers. Data were adjusted for baseline event rate and pooled using a random-effects model. Bayesian predictive effects and intervals were calculated to indicate the variance in outcomes that would be expected if new studies were conducted in the future.

RESULTS

Eighteen studies (16 prospective, two cross-sectional) were included, with 794,577 participants. Fifteen of these studies were moderate to high quality. The greatest sedentary time compared with the lowest was associated with a 112% increase in the RR of diabetes (RR 2.12; 95% credible interval [CrI] 1.61, 2.78), a 147% increase in the RR of cardiovascular events (RR 2.47; 95% CI 1.44, 4.24), a 90% increase in the risk of cardiovascular mortality (HR 1.90; 95% CrI 1.36, 2.66) and a 49% increase in the risk of all-cause mortality (HR 1.49; 95% CrI 1.14, 2.03). The predictive effects and intervals were only significant for diabetes.

CONCLUSIONS/INTERPRETATION

Sedentary time is associated with an increased risk of diabetes, cardiovascular disease and cardiovascular and all-cause mortality; the strength of the association is most consistent for diabetes.

Too much sitting--a health hazard

In contemporary society, prolonged sitting has been engineered into our lives across many settings, including transportation, the workplace, and the home. There is new evidence that too much sitting (also known as sedentary behavior - which involves very low energy expenditure, such as television viewing and desk-bound work) is adversely associated with health outcomes, including cardio-metabolic risk biomarkers, type 2 diabetes and premature mortality. Importantly, these detrimental associations remain even after accounting for time spent in leisure time physical activity. We describe recent evidence from epidemiological and experimental studies that makes a persuasive case that too much sitting should now be considered an important stand-alone component of the physical activity and health equation, particularly in relation to diabetes and cardiovascular risk. We highlight directions for further research and consider some of the practical implications of focusing on too much sitting as a modifiable health risk.

Adult sedentary behavior: a systematic review

CONTEXT

While the health benefits of meeting moderate/vigorous-intensity physical activity (MVPA) guidelines have been well established, the health risks of sedentary behavior, independent of meeting MVPA guidelines, are becoming evident. Sedentary behavior may require different interventions, based on correlates that differ from MVPA. The current review aimed to collect and appraise the current literature on correlates of sedentary behaviors among adults.

EVIDENCE ACQUISITION

Papers were considered eligible if they were published in English-language peer-reviewed journals and examined correlates of sedentary behaviors. Literature searches were conducted in August 2011 among ten search engines yielding 3691 potentially relevant records; of these, 109 papers (82 independent samples) passed eligibility criteria.

EVIDENCE SYNTHESIS

Articles included were published between 1982 and 2011, with sample sizes ranging from 39 to 123,216. Eighty-three were cross-sectional, 24 followed a prospective design, one was experimental baseline data, and one was cohort design. Sedentary behavior was primarily measured as TV viewing or computer use, followed by analysis of a more omnibus assessment of time spent sitting. Evidence was present for sedentary behavior and correlates of education, age, employment status, gender, BMI, income, smoking status, MVPA, attitudes, and depressive symptoms/quality of life. Notable differences by specific sedentary behaviors were present that aided in the explanation of findings.

CONCLUSIONS

Results point to the high specificity of various sedentary behaviors (e.g., TV viewing vs sitting and socializing), suggesting that the research domain is complex and cannot be considered the simple absence of MVPA. Several sociodemographic and health factors appear reliably linked to sedentary behavior, yet there is an obvious absence of research focused on cognitive, social, and environmental factors that could be of use in anti-sedentary behavior interventions.

Gestational Diabetes

Gestational diabetes mellitus (GDM) is one of the most common complications of pregnancy and is strongly related to subsequent risk of type 2 diabetes. The epidemics of obesity and diabetes and the increasing incidence of GDM in recent years highlight the importance of preventing GDM among women at high risk to avoid the associated short- and long-term adverse health outcomes for both mothers and their offspring. Indeed, women may be more likely to adopt healthy lifestyle habits during pregnancy and maintain these habits into the postpartum period. Although there is substantial evidence that targeting at-risk groups for type 2 diabetes prevention is effective if lifestyle changes are made, relatively little attention has been paid to the prevention of GDM. Therefore, the objective of this article is to review the scientific evidence regarding the association between modifiable risk factors and GDM; discuss how lifestyle interventions, including weight management through diet and exercise could be successful in reducing the risk for GDM; and provide recommendations for future lifestyle intervention programs with a focus on translation and dissemination of research findings.

Steps to preventing type 2 diabetes: exercise, walk more, or sit less?

Accumulated evidence supports the promotion of structured exercise for treating prediabetes and preventing Type 2 diabetes. Unfortunately, contemporary societal changes in lifestyle behaviors (occupational, domestic, transportation, and leisure-time) have resulted in a notable widespread deficiency of non-exercise physical activity (e.g., ambulatory activity undertaken outside the context of purposeful exercise) that has been simultaneously exchanged for an excess in sedentary behaviors (e.g., desk work, labor saving devices, motor vehicle travel, and screen-based leisure-time pursuits). It is possible that the known beneficial effects of more structured forms of exercise are attenuated or otherwise undermined against this backdrop of normalized and ubiquitous slothful living. Although public health guidelines have traditionally focused on promoting a detailed exercise prescription, it is evident that the emergent need is to revise and expand the message to address this insidious and deleterious lifestyle shift. Specifically, we recommend that adults avoid averaging <5,000 steps/day and strive to average ≥7,500 steps/day, of which ≥3,000 steps (representing at least 30 min) should be taken at a cadence ≥100 steps/min. They should also practice regularly breaking up extended bouts of sitting with ambulatory activity. Simply put, we must consider advocating a whole message to "walk more, sit less, and exercise."

The influence of neighborhood socioeconomic status and walkability on TV viewing time

BACKGROUND

Influences on TV viewing time, which is associated with adverse health outcomes such as obesity and diabetes, need clarification. We assessed the relation of neighborhood socioeconomic status (SES) and walkability with TV viewing time in the Black Women's Health Study, a prospective study of African American women.

METHODS

We created neighborhood SES and walkability scores using data from the U.S. census and other sources. We estimated odds ratios for TV viewing 5+ hours/day compared with 0-1 hours/day for quintiles of neighborhood SES and walkability scores.

RESULTS

Neighborhood SES was inversely associated with TV viewing time. The odds ratio for watching 5+ hours/day in the highest compared with the lowest quintile of neighborhood SES was 0.66 (95% CI 0.54-0.81). Neighborhood walkability was not associated with TV viewing time.

CONCLUSIONS

Neighborhood SES should be considered in devising strategies to combat the high levels of sedentariness prevalent in African American women.

Television Viewing Does Not Have to Be Sedentary: Motivation to Participate in a TV Exercise Program

The present study explored which underlying motivations induced people to participate in a television exercise program called "The Netherlands on the Move!-television" (NOM-tv). A cross-sectional study was carried out among 1,349 viewers of NOM-tv. The respondents completed the intrinsic motivation inventory (IMI), assessing their levels of intrinsic motivation towards participating in the NOM-tv exercises. The results showed that higher levels of intrinsic motivation (i.e. enjoying the NOM-tv exercises, feeling competent to perform this activity, and willingness to put effort into the exercises) were the most important predictive factors of more frequent participation in the NOM-tv exercises. Future screen-based interventions to reduce sedentary behavior should aim especially at encouraging people's intrinsic orientations towards physical activity in an autonomy-supportive way.

Multiple measures of physical activity, dietary habits and weight status in African American and Hispanic or Latina women

Compared measures of physical activity and dietary habits used in the Health Is Power (HIP) study, and described the associations of physical activity and dietary habits among African American and Hispanic or Latino women, adjusted for weight status. Cross-sectional baseline data were compared for community dwelling, healthy African American (N = 262) and Hispanic or Latina women (N = 148) who participated in HIP. Physical activity was measured using the International Physical Activity Questionnaire (IPAQ) long form, the Check And Line Questionnaire (CALQ) log and accelerometry. Dietary habits were measured using NCI 24-h recall screeners, vegetable and fruit (VF) logs and the NCI Diet History Questionnaire (DHQ). Differences in physical activity and dietary habits were assessed using simultaneous 2 (ethnicity) × 3 (weight status) ANCOVAs adjusted for age and socioeconomic status. Women (M age = 44.4 ± 10.9 years) were obese (M = 34.0 ± 9.7 kg/m(2)), did not meet physical activity guidelines as measured by accelerometry (M = 19.4 ± 19.1 min MVPA/day) and ate few VF (M = 2.8 ± 2.7 servings/day). DHQ variables differed by weight status. IPAQ was associated with CALQ, and CALQ with accelerometry (P < .05). IPAQ was not associated with accelerometry. Regardless of ethnicity, normal weight women did more physical activity, reported more VF consumption, and consumed more fat calories than overweight and obese women (Ps < .05). African American women did more MVPA than Hispanic or Latino women (P < .001). Relationships between behaviors and weight status suggest accelerometry and DHQ are preferable, regardless of ethnicity; and studies may capture different domains of physical activity and dietary habits depending on measure used.

Factors associated with physical activity levels in African-American women with type 2 diabetes

PURPOSE

To examine how family/friend social support, exercise self-efficacy, physical environment, sense of community, social issues and roles, socioeconomic status, and body image discrepancy influence physical activity levels in African American females with type 2 diabetes.

DATA SOURCES

A sample of 50 African American females with type 2 diabetes was recruited from a Midwest diabetes center for this descriptive, cross-sectional, correlational study. A series of self-report instruments were administered to examine the relationships between the independent study variables and physical activity levels.

CONCLUSIONS

Results of the study suggested that higher levels of exercise self-efficacy, family social support for exercise, and a decrease in physical environmental barriers may serve to increase physical activity levels in this population. No significant relationships were observed between the other study variables and physical activity levels.

IMPLICATIONS FOR PRACTICE

Nurse practitioners working with African American females with type 2 diabetes need to assess family social support, exercise self-efficacy, and physical environmental barriers and plan interventions that incorporate family support and the principles of self-efficacy while minimizing environmental barriers. Further exploration is warranted to examine the relationship between body image discrepancy and physical activity in this population.

Sitting time and Body Mass Index in diabetics and pre-diabetics willing to participate in a lifestyle intervention

This cross-sectional study examined the relationship between Body Mass Index (BMI), total sitting time and total physical activity time in a generally overweight or obese population of type 2 diabetics or pre-diabetics willing to participate in a lifestyle intervention [n = 221, 55.1% male, mean age (SD) 62.0 (9.9), mean BMI (SD) 31.4 (5.0)]. In addition, we aimed to identify demographic and psychosocial associates of the motivation to become more physically active. The measurement instrument was a self-report questionnaire. Results showed that total sitting time was more closely related to BMI than total physical activity time. Subjects with a higher weight status were more sedentary, but they were also more motivated to be physically active. On the other hand, their self-efficacy to be physically active was lower than subjects with a lower weight status. Lifestyle interventions to decrease the risk of obesity and type 2 diabetes should aim not only at increasing total physical activity time, but also at reducing the total sitting time. Despite generally high levels of motivation among these obese participants, intervention designers and intermediaries should be aware of their low level of self-efficacy towards being physically active.

Television viewing and risk of type 2 diabetes, cardiovascular disease, and all-cause mortality: a meta-analysis

CONTEXT

Prolonged television (TV) viewing is the most prevalent and pervasive sedentary behavior in industrialized countries and has been associated with morbidity and mortality. However, a systematic and quantitative assessment of published studies is not available.

OBJECTIVE

To perform a meta-analysis of all prospective cohort studies to determine the association between TV viewing and risk of type 2 diabetes, fatal or nonfatal cardiovascular disease, and all-cause mortality.

DATA SOURCES AND STUDY SELECTION

Relevant studies were identified by searches of the MEDLINE database from 1970 to March 2011 and the EMBASE database from 1974 to March 2011 without restrictions and by reviewing reference lists from retrieved articles. Cohort studies that reported relative risk estimates with 95% confidence intervals (CIs) for the associations of interest were included.

DATA EXTRACTION

Data were extracted independently by each author and summary estimates of association were obtained using a random-effects model.

DATA SYNTHESIS

Of the 8 studies included, 4 reported results on type 2 diabetes (175,938 individuals; 6428 incident cases during 1.1 million person-years of follow-up), 4 reported on fatal or nonfatal cardiovascular disease (34,253 individuals; 1052 incident cases), and 3 reported on all-cause mortality (26,509 individuals; 1879 deaths during 202,353 person-years of follow-up). The pooled relative risks per 2 hours of TV viewing per day were 1.20 (95% CI, 1.14-1.27) for type 2 diabetes, 1.15 (95% CI, 1.06-1.23) for fatal or nonfatal cardiovascular disease, and 1.13 (95% CI, 1.07-1.18) for all-cause mortality. While the associations between time spent viewing TV and risk of type 2 diabetes and cardiovascular disease were linear, the risk of all-cause mortality appeared to increase with TV viewing duration of greater than 3 hours per day. The estimated absolute risk differences per every 2 hours of TV viewing per day were 176 cases of type 2 diabetes per 100,000 individuals per year, 38 cases of fatal cardiovascular disease per 100,000 individuals per year, and 104 deaths for all-cause mortality per 100,000 individuals per year.

CONCLUSION

Prolonged TV viewing was associated with increased risk of type 2 diabetes, cardiovascular disease, and all-cause mortality.

An ethic of resistance: choosing life in health messages for African American women

Media messages directed to African American women are more likely to have health content that emphasizes negative outcomes or sexual stereotypes. This paper critiques the use of health messages that focus on high mortality and morbidity rates, yet have not reduced health disparities, but have instead reduced Black women's bodies to carriers of disease. I introduce an ethic of resistance that privileges the authority and wholeness of Black women rather than disease and fragmentation. An ethic of resistance helps Black women connect to their spiritual health, move from passive receiver to active resister of negative messages, and break the generational silence to demystify sexuality and integrate it into a lifestyle of wholeness. My hope is to improve the health outcomes of African American women by improving the message.

Association of physical activity with risk of type 2 diabetes

BACKGROUND

Physical activity has shown to prevent type diabetes 2. However, the type, intensity and amount of effective physical activity as well as individuals' needs according to level of their risk for type 2 diabetes have not been clarified comprehensively. This study investigated a relation between moderate aerobic physical activity ≥150 minuets/week with decreased risk of type 2 diabetes among obese and non-obese residents of south of Tehran, Iran.

METHODS

This study, which was a part of the Cardiovascular Risk Factors Survey in Tehran population Lab region, was designed and conducted based on MONICA/WHO project. Totally, 1552 adult inhabitants of 17th district of Tehran were enrolled in this cross-sectional study. Physical activity was assessed by MONICA Optional Study of Physical Activity questionnaire. Diabetes was defined as a history of a prior diagnosis of diabetes or fasting serum glucose ≥126 mg/dl. All data analyses were conducted using SPSS 17 software for Windows

RESULTS

In a multivariate model, moderate aerobic physical activity ≥150 minuets/week was significantly associated with decreased risk of type 2 diabetes in all and non-obese subjects [OR= 0.56; 95%CI: 0.35-0.91 and OR= 0.50; 95%CI: 0.26-0.94, respectively]. There was no significant relation between the physical activity and type 2 diabetes risk in obese subjects [OR=0.64; 95%CI: 0.30-1.39].

CONCLUSION

Moderate aerobic physical activity ≥150 minuets/week was significantly associated with decreased risk of type 2 diabetes in non-obese people and could be an acceptable exercise goal for these individuals. However, obese people should be investigated more to produce a tailored exercise guideline to this population at high risk of type 2 diabetes.

Habitual physical activity can be increased in people with cerebral palsy: a systematic review

Objective: To determine if habitual physical activity could be increased in people with cerebral palsy.

Data sources: We searched electronic databases until February 2010 using key words related to concepts of cerebral palsy and physical activity. This search was supplemented with citation tracking.

Methods: Studies had to include participants with cerebral palsy who have habitual physical activity measured over at least one day after a therapy intervention. Two reviewers independently assessed study quality with the PEDro scale (quantitative studies) and Critical Appraisal Checklist for Qualitative Research (qualitative studies). For quantitative studies standardized mean differences were calculated and meta-analysis conducted. Qualitative data were synthesized thematically.

Results: Three randomized controlled trials (96 participants) and two qualitative studies (21 participants) were reviewed. Four studies evaluated exercise programmes, and one study an online educational and support programme. Meta-analysis showed that exercise programmes could increase habitual physical activity (δ = 1.0; 95% confidence interval (CI) 0.28 to 1.72). This result was reinforced by reports of increased daily activity in two qualitative studies. The online programme increased weekly minutes of moderate to vigorous physical activity (d = 0.81; 95% CI 0.17 to 1.45), and weekly step counts (d = 0.62; 95% CI 0.0 to 1.25). Positive effects were not maintained after programmes stopped. There was insufficient evidence to determine if demographic factors or programme characteristics, such as intensity and setting, were associated with outcomes.

Conclusion: Preliminary evidence suggests that exercise programmes and online support programmes can increase habitual physical activity in people with cerebral palsy, but effects are not maintained when programmes stop.

Sedentary behaviors and abnormal glucose tolerance among pregnant Latina women

Studies conducted among nonpregnant populations have observed an association between sedentary behavior and glucose intolerance. Few studies have investigated this association during pregnancy, particularly among Latina women, a population with higher rates of sedentary behavior and abnormal glucose tolerance (AGT) as compared with non-Latina white women.

OBJECTIVE

The purpose of this study was to estimate the association between sedentary behavior and AGT.

RESEARCH DESIGN AND METHODS

We used data from the Latina gestational diabetes mellitus study, a prospective cohort of 1231 Latina prenatal care patients in western Massachusetts. Sedentary behavior was assessed by bilingual interviewers using a modified version of the Kaiser Physical Activity Survey in prepregnancy, early pregnancy, and midpregnancy and defined as hours spent TV watching, frequency of sitting at work, and participation in sports or exercise activity as well as a derived composite of total sedentary activity. AGT was measured at 24-28 wk of gestation and abstracted from medical records after delivery. Multivariate logistic regression was used to calculate odds ratios and 95% confidence intervals.

RESULTS

A total of 12% (n = 119) of participants were classified as having AGT. After adjusting for AGT risk factors, sedentary behaviors in prepregnancy or in early pregnancy were not associated with AGT. However, in midpregnancy, low levels of participation in sports or exercise (odds ratio = 2.01, 95% CI = 1.01-4.02) and increasing total sedentary activity (Ptrend = 0.003) were associated with increased risk for AGT.

CONCLUSIONS

Findings suggest an association between sedentary activity in midpregnancy and risk of AGT in this understudied population.